Gravure printing due to the thicker ink layer, so the problem of poor drying always exists. Gravure printing is characterized by wet stacking wet, although there is a long drying channel, but gravure printing in the stack of colors in the previous color group of ink is not dry, just in the ink layer surface of a film to prevent the latter group of inks in the stack of colors to the former color of the ink anti-sticking.

Seven reasons why gravure products don't dry well:

1, the gravure screen cavity is deeper, sometimes the depth reaches 60μm, the amount of ink on the large, drying will be difficult.

2, in order to ensure the transfer of high-gloss small dots, gravure printing process must be added to the slow drying agent, which will also affect the drying effect of the ink.

3, the integrated balance of mixed solvents is not easy to master, resulting in a large number of slow drying agent retention.

4, some of the printing process, the last color printing white ink, and then reeling, drying and reeling station between the distance is too short, drying difficulties. And white ink bottoming requires ink with good covering power, can only thicken the ink layer. Generally speaking, the amount of ink on white ink is the largest of all colors.

5, film printing, the temperature of the drying device can not be too high, the drying channel can not be too long, otherwise the film will be stretched and deformed, affecting the overprint accuracy and product length. Commonly used method is to use low temperature, large air volume, in the drying process using volatile way, give up the evaporation.

6, the solvent volatilization on the dependence of environmental conditions, when the environment of the air pressure is relatively low, with a mechanical exhaust device is difficult to effectively control the drying performance.

7, the ink layer on the surface of the printed matter with the atmosphere on the contact surface there is a demarcation layer (foreign counterparts known as "Boundarylayer", some people translate it as "mirror film"), which is a layer of hot air and solvent vapors contained in the mixture. Higher temperature.

Ink drying under the action of high temperature, in which the liquid solvent will evaporate and move to the demarcation layer, if no solvent in the demarcation layer, the solvent vapor is easily transferred to the atmosphere. But with the rising concentration of solvent vapor in the demarcation layer, the evaporation rate of solvent will be reduced, when the solvent vapor in the demarcation layer tends to be saturated, the evaporation process will stop. The traditional gravure drying process does not pay attention to the existence of the demarcation layer, ignoring the role of evaporation in the drying, although the industry has made some improvements to the curve of the gravure drying channel to reduce the wind resistance, improve the air volume, but due to the existence of this layer of the demarcation layer does not follow the flow of air, some of the ink in the residual solvents are not volatile will still be wrapped up in it.